The invention relates in general to agricultural combines. It relates particularly to a combine with a corn harvesting header assembly.
It is conventional in combines fitted with corn harvesting header assemblies to employ a sprocket and chain drive for the line shaft which drives each of the individual row harvesting units in a header assembly. A drive sprocket on a power jack shaft off the combine feeder is connected by a drive chain to a driven sprocket on the header assembly. The driven sprocket is, in turn, conventionally connected to the line shaft, either directly or indirectly. One example of this type of drive system is illustrated and described in Schreiner et al. U.S. Pat. No. 3,759,021. Another is illustrated and described in Pucher U.S. Pat. No. 4,227,366.
This type of drive system, already long in use on corn harvesting combines, is relatively expensive to maintain, although it has served well for many years. Chain and belt components must be replaced frequently because of wear and damage. Dust and dirt accumulate rapidly in the chains, belts, sprockets and pulleys, accelerating wear. Development of an improved drive system has long been considered but, to this date, never realized.
It is an object of the present invention to provide an improved drive system for the row units of a corn harvesting header assembly on a combine.
It is another object to provide an improved drive system of the aforedescribed character which eliminates the need for sprockets, pulleys, drive chains and drive belts in a row unit drive system.
It is still another object to provide an improved drive system for the row units of a corn harvesting header assembly wherein the drive connection from the combine to the row units can be made anywhere along the line shaft which drives each of the row units.
It is yet another object to provide an improved row unit drive system for a corn harvesting header assembly wherein gearbox loads are transmitted to the combine frame and bending loads on the line shaft(s) are minimized.
The foregoing and other objects are realized in a drive system which includes a right angle gearbox connection to the jack-shaft on the combine feeder. The right angle gear set has an output coupler shaft extending forwardly of the combine for a predetermined distance. It provides the input to a Tee gear set between two row unit drive gearboxes. The right angle gear set and Tee gear may be contained in a simple housing or gearbox, which is the preferred construction, or they may be contained in separate housings. In the latter case, the two gearboxes are also connected by a mounting bracket which holds the gear boxes in alignment, transmits gearbox loads to the combine frame and shields the coupler shaft.
The line shaft normally extends across the width of the header assembly and passes through each corn head row unit drive gear box in doing so, crossing the Tee in the Tee gear set. The line shaft is then driven as a function of PTO shaft output, from the right angle gear set through the Tee gear set. Where wider header assemblies are involved, two axially aligned line shafts may be employed. In such case, they may be coupled and driven by a single drive system embodying the invention or, in the alternative, by two such drive systems.